Not applicable.
Not applicable.
The invention relates to a device for the application of fluid materials to a surface of a sheet-form material, with an application roller which has a roller body with an outer surface which when at least partially abutting on the sheet-form material transfers the fluid material to the sheet-form material.
Numerous apparatuses are already known for the application of fluid materials to a surface of a sheet-form material. Each of these apparatuses requires a special adaptation to the respective materials to be applied and to the circumstances as regards the properties of the sheet-form material, processing temperature, speed and the amount of the material to be applied and also the kind of the material to be applied.
In laminating at least two sheet-form materials it is necessary that a defined amount of fluid materials, particularly adhesive, is applied to at least a first layer of the sheet-form material, so that this layer is applied to at least a further layer of a sheet-form material and remains on this at least one layer of the sheet-form material due to a resulting adhesive bond. The sheet-form material can be, for example, very thin polymer foils or carrier layers, which are extremely sensitive to tensions. Furthermore, a further layer can be laminated, for example, onto a layer with visual information. For this, it is necessary that a uniform bonding between the layers is made possible, so that the information can be recognized and examined.
The use of fluid materials, particularly adhesives, which are taken up by an application roller from a supply region and transferred to the sheet-form material, is necessary for the lamination of layers. In this process of applying the fluid material to the sheet-form material, particularly in the case of adhesives, a soiling of the application roller and its bearing regions occurs. The functional ability or the rotation of the application roller can thereby be worsened or even stopped, which can result in an uneven application of the fluid material to the sheet-form material, or an application of the fluid material to the sheet-form material is rendered impossible.
The invention therefore has as its object to provide an apparatus for the application of fluid materials to the surface of a sheet-form material, which makes possible a uniform application of a set thickness of a film during a very long duration of operation.
This object is attained with a metering doctor to which a pre-metering channel leads for provision of the fluid material and at least partially wets the application roller with fluid material. A flow of a medium directed substantially outward from a longitudinal mid-axis of the application roller is provided at least in a region bordering on the outer surface of the application roller.
By the use of a medium which at least partially flows radially outward in the edge region of the roller body of the application roller, it is made possible that the fluid material, seen in the axial direction, does not leave the outside surface of the roller body at least in the direction of the bearing regions of the application roller, so that a penetration of the fluid material to the bearing regions of the application roller is prevented. By the bounding of the outside surface by means of a fluid medium, a defined application width of the fluid material on the surface of the sheet-form material can be given, which can be adjusted to the requirements for the further processing of the sheet-form material onto a further layer of a sheet-form material, particularly when the sheet-form material is wider than the outside surface of the application roller.
The air flowing out in the edge region of the roller body of the application roller forms a seal of the bearing region, which furthermore makes it possible for the application roller to be used both for a so-called flying coating, in which the application roller works solely against a sheet tension of the sheet-form material, and also for a coating with the use of a counterpressure roller.
According to an advantageous embodiment of the invention, it is provided that at least one axial bore is provided at least at one end of the application roller, and cross bores branch off therefrom, preferably in the edge region of the outside surface. The medium, preferably under pressure, can thereby be supplied in a simple manner to the edge region of the outside surface, so that a lateral sealing of the application roller relative to the respective bearing is made possible.
According to a further advantageous embodiment of the invention, it is provided that a receiving member is provided at each end of the roller body and forms with the edge region of the roller body a gap leading outward. Sealing of the bearing regions and limitation of the outside surface of the roller body as application surface is thus made possible. It is advantageously provided that the receiving member at least partially covers the cross bore. A guide channel or gap for the medium can thus be formed by a receiving member in a simple manner, and is constituted as far as the outside surface of the roller body.
According to a further advantageous embodiment of the invention, it is provided that the receiving member is constituted as a bearing and has a bearing section for receiving the application roller. Thereby on the one hand, the number of components is reduced, and also, on the other hand, simple and rapid mounting is made possible.
According to a further advantageous embodiment of the invention, it is provided that the end face of the roller body and the surface of the receiving member arranged complementary thereto form a gap which is directed at right angles to the longitudinal axis of the application roller or at an angle in the direction of the edge region of the sheet-form material or of the bearing regions. A fluid material possibly overflowing over the edge region of the outside surface of the roller body can thereby be guided away laterally outward, without the set coating thickness of the fluid material on the sheet-form material being adversely affected.
According to a further advantageous embodiment of the invention, it is provided that the gap between the end face of the roller body and the receiving member is adjustable. The sealing can thereby take into account the respective case of application and the sensitivities of the fluid material and of the sheet-form materials. The flow speed of the medium which flows outward through the gap can advantageously be likewise adjustable.
According to a further advantageous embodiment of the invention, it is provided that a UV crosslinking-active adhesive is provided. In particular, this embodiment is of particular advantage with these adhesives which immediately harden or polymerize when subjected to shear.
According to a further advantageous embodiment of the invention, it is provided that compressed air us used as the medium. A cost-favorable embodiment can thereby be given, since the surrounding air can be compressed and used. It can alternatively be provided that special gases or liquid media or the like are used in order to effect a sealing of the bearing regions.
According to a further advantageous embodiment of the invention, it is provided that the application roller is received by adjustable bearings. It is thereby made possible for the amount of the fluid material taken up from a metering region of the application roller to be adjustable. The bearings can also serve as an additional possibility of adjustment to the metering doctor. Furthermore, changes due to the use of the application roller and possibly of the bearings can be adjusted for.
According to a further advantageous embodiment of the invention, it is provided that the rotation speed of the application roller is equal to or smaller than the sheet speed of the sheet-form material. Thereby a more uniform and thinner film of a fluid material can be applied. In this mode of operation, it can advantageously be provided that the sheet-form material abuts the application roller under tension, which can be adjusted by means of a guide roller before and after the application roller in the sheet forwarding direction.